Win at least one Jam race for three rounds in a row. Each Jam round goes from Thursday to Thursday, so this achievement takes a bit of time.
There's additional achievements for 10, 50 and 100 rounds in a row.
You'll need to connect your Mad Skills BMX 2 game to one of the available social networks to set up an account with the game. Then simply tap the Jam card on the main menu and complete one of the available races.
Make sure you do the same thing during the next two Jam rounds/weeks, and you'll unlock this achievement.